Band gaps of primary metallic carbon nanotubes

Abstract

Primary metallic, or small gap semiconducting nanotubes, are tubes with band\ngaps that arise solely from breaking the bond symmetry due to the curvature. We\nderive an analytic expression for these gaps by considering how a general\nsymmetry breaking opens a gap in nanotubes with a well defined chiral wrapping\nvector. This approach provides a straightforward way to include all types of\nsymmetry breaking effects, resulting in a simple unified gap equation as a\nfunction of chirality and deformations.\n